Adds Analog Gain Control (AGC) to the WebRTC client.

content/browser/renderer_host/media/audio_input_renderer_host.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // AudioInputRendererHost serves audio related requests from audio capturer
 // which lives inside the render process and provide access to audio hardware.
 //
 // Create stream sequence (AudioInputController = AIC):
 //
 // AudioInputHostMsg_CreateStream -> OnCreateStream -> AIC::CreateLowLatency ->
@@ skipping 122 matching lines @@
   // Start the audio input device with the session id. If the device
   // starts successfully, it will trigger OnDeviceStarted() callback.
   void OnStartDevice(int stream_id, int session_id);
 
   // Audio related IPC message handlers.
   // Creates an audio input stream with the specified format. If this call is
   // successful this object would keep an internal entry of the stream for the
   // required properties.
   void OnCreateStream(int stream_id,
                       const AudioParameters& params,
-                      const std::string& device_id);
+                      const std::string& device_id,
+                      bool automatic_gain_control);
 
   // Record the audio input stream referenced by |stream_id|.
   void OnRecordStream(int stream_id);
 
   // Close the audio stream referenced by |stream_id|.
   void OnCloseStream(int stream_id);
 
   // Set the volume of the audio stream referenced by |stream_id|.
   void OnSetVolume(int stream_id, double volume);
 
   // Get the volume of the audio stream referenced by |stream_id|.
   void OnGetVolume(int stream_id);
 
+  // Set the automatic gain control state for the audio stream referenced
+  // by |stream_id|.
+  void OnSetAutomaticGainControl(int stream_id, bool enabled);
+
   // Complete the process of creating an audio input stream. This will set up
   // the shared memory or shared socket in low latency mode.
   void DoCompleteCreation(media::AudioInputController* controller);
 
   // Send a state change message to the renderer.
   void DoSendRecordingMessage(media::AudioInputController* controller);
   void DoSendPausedMessage(media::AudioInputController* controller);
 
   // Handle error coming from audio stream.
   void DoHandleError(media::AudioInputController* controller, int error_code);
@@ skipping 42 matching lines @@
   AudioEntryMap audio_entries_;
 
   // A map of session IDs to audio session sources.
   typedef std::map<int, int> SessionEntryMap;
   SessionEntryMap session_entries_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioInputRendererHost);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_AUDIO_INPUT_RENDERER_HOST_H_